Extruder screw barrel heating method
Machine heating uses resistance heating widely, and uses thermocouples to achieve segmented temperature control and inspection. Resistance heating is the use of resistance to generate heat to heat the barrel, and then transfer the heat to the plastic in the barrel. Resistance heating mainly includes band heaters, cast aluminum heaters, ceramic heaters, etc. These heaters have the advantages of small size, easy manufacturing and maintenance.
Temperature range of granulator barrel
According to the different plasticization states of the material along the axis of the screw, in order to make the barrel distribution of the barrel meet the requirements of the injection molding process, the heating of the screw machine must be carried out in stages to help improve the plasticization ability. Generally, (3-5) Ds, (Ds is the rod diameter) is a heating temperature control section, and the heating temperature control fluctuation range should generally not exceed 5 ℃, and the heat sensitive plastic should preferably not exceed 2 ℃.
Extruder screw barrel heating power
When determining the heating power of the barrel, in addition to considering the heat required for plasticization, it also needs to meet the productivity requirements of the injection molding machine to ensure that the barrel has a sufficiently rapid heating rate. The heating time of the machine heating is not more than 30min for small machines, and generally about 1h for large and medium-sized machines.
Extruder screw barrel cooling
① Under normal circumstances, the barrel does not need to be equipped with a cooling control system, and it can meet the process requirements by natural cooling. However, if the temperature of the feed inlet is too high, the phenomenon of "bridging" will occur at the feed inlet, making the feeding difficult or even impossible.
② In order to ensure good feeding and solid material transportation conditions and prevent the heat of the barrel from being transmitted to the transmission parts, a cooling jacket (slot) should be provided at the feed port of the barrel, and the amount of cooling water can be adjusted according to the process requirements. In addition, when processing heat-sensitive plastics at a higher speed, the machine must be cooled and controlled to prevent the heat-sensitive plastics from being decomposed by heat.